Field of the Invention
The invention relates to a hurdle or rack board for separating sheet piles in a delivery of a sheet-fed printing machine. Hurdle boards are panels or pallets which, in the delivery of a sheet-fed printing machine, are positioned on a pile board and then above one another, with an interposition of spacer elements, respectively, in order to form a relatively low partial pile of sheets of paper or other printing materials, respectively, thereon. Such a hurdle operation is necessary if sheets in a relatively high pile were to stick together as a result of the weight of the pile, as can occur, for example, in the case of intensive ink application and/or thin printing materials. The spacer elements keep the hurdle boards spaced apart from one another a distance that is greater than the height of the individual partial piles, with the result that the pile pressure is limited, and blocking of sheets is prevented.
In the case of hurdle work or operation, the machine operator usually positions, for example, four spacer elements manually around the last-formed partial pile, on the pile board or on the uppermost of the hurdle boards which, for this purpose are somewhat larger than the maximum printable sheet format, and then places the next hurdle board in position, in which case, the operator must be careful not to move the spacer elements. These handling procedures are also necessary in the case of a delivery for non-stop operation, as is described, for example, in the published German Patent Document DE-A-4 344 361. In such a case, the introduction and positioning of the spacer elements is not merely laborious, but also, due to the continuing operation of the printing machine, very dangerous, in particular in the case of the rear or inner spacer elements, for which the operator has to reach far into the delivery.